You had no choice but to be honest as there ARE records of each of these arrests. Also, you (and everyone else here) need to understand that there is no such thing as an expunged record. Expunging it means that you are trying to conceal it. If you did not declare either one of these you can be terminated from the process for dishonesty.

Here are a couple of things the background investigator will consider. Whether or not you were found guilty is oftentimes immaterial in a background investigation. Here is the question to ask:
Were you involved in a fight?
Did you drive with alcohol in your system?

Whether or not you were convicted really doesn't significantly change the fact that a Fire Chief does not want to hire someone who is going to bring discredit to his department. One event can be overlooked, but two begin to show a pattern. Speaking of patterns, I suspect you may have a pattern of heavy drinking (evidenced by the DUI) and a history of fighting (evidenced by the assault charge).

These patterns are enough, in and of themselves, to disqualify a candidate from a background investigation. The arrests are just icing on the cake. I would suspect your background investigator revealed a pattern of heavy drinking. I suspect there was probably alcohol involved in the assault charge (demonstrates a pattern).

Again, I do not know you or yor personal situation, however I have reviewed a lot of candidate's background packets.

Thank you for all the info. It's hard to stay positive dealing with this. I was 18 and 21 when those events occurred and I have done a lot of growing up since then. Hopefully I can find a department that will look past those mistakes. Also on the application it asked if I have ever been "convicted" of anything so I don't disclose anything on the applications.

I would not advocate declaring it on the application if it does NOT ask for it. The application is viewed by the oral board members and it will absolutely taint their opinion of you.
Time is your best frind, especially since these incidents occurred a few years back. More importantly, I would encourage you to QUIT DRINKING. This is the best way to show that you have changed.
Best of luct to you and remember that time is your best friend when it comes to a background issue.

Time time time. 4 years since a DUI arrest (even if u were found not guilty) isn't that long ago. I have a class a mis and was turned down a few times. Just keep testing, studying and keep a good attiditude. Everyone makes mistakes.